In recent years regulatory agencies around the world have instituted changes in the regulations governing the emission levels of power generation systems. The changing of these regulations has resulted in many manufacturers of power generation systems producing aftertreatment systems to be added to their power generation systems. These aftertreatment systems reduce the levels of regulated emissions produced by the power generation systems.
The elements of a power generation aftertreatment system are selected dependent upon (i) the regulations in the region in which the system is to be used and (ii) the type of power source in the power generation system. For example, if the power source uses diesel fuel, some regulations may require that a particulate filter be included in the aftertreatment system to reduce the particulate emissions of the power generation system. In contrast, if the power source uses natural gas as fuel, a particulate filter is typically not needed because the particulates produced by natural gas combustion are typically below emission regulation levels. Regulations in some regions limit the level of noise produced by power generation systems. To comply with these regulations, a noise reduction device, such as a muffler, is often connected to the power generation system.
Another factor in the design of power generation aftertreatment systems is the space in which the aftertreatment system must fit. Many power generation systems are used in areas with tight space constraints, and therefore the aftertreatment system must be as compact as possible. In addition, a smaller aftertreatment system will likely be easier and more economical to transport.
Current power generation aftertreatment systems cannot easily be modified to be used on different types of power generation systems. This limitation of current aftertreatment systems is particularly detrimental to companies that purchase power generation systems and rent them to others. Such companies must purchase several different types of aftertreatment systems to keep in inventory, not knowing which type of power generation system a potential customer may need. This additional inventory increases the capital expenditures of the companies and reduces their profit.
The typical process of attaching aftertreatment systems to power generation systems involves attaching individual elements of the aftertreatment system to the housing of the power generation system. However, a typical aftertreatment system includes several aftertreatment elements that each must be attached to the power generation system. Therefore, several laborers must travel to the site where the power generation system is located, determine the proper location for each aftertreatment element, prepare the power generation system for the attachment of the aftertreatment elements, attach each aftertreatment element to the power generation system, and connect the aftertreatment elements to each other and to the exhaust of the power generation system. This process is both time consuming and expensive.
When an aftertreatment system is to be added to a portable power generation system, other difficulties arise. The top sides of the housings of most portable power generation systems are not strong enough to support the weight of an aftertreatment system. Therefore, a typical procedure for attaching an aftertreatment system to a portable power generation system includes attaching supporting members to a side of the housing of the portable power generation system. These supporting members typically have one end welded to the base of the housing, a body that extends vertically up the side of the housing, and another end that extends above the top side of the housing. The aftertreatment elements are then attached to these members. Adding these supporting members to the housing increases the time and expense required to install the aftertreatment system.
Transportation problems are also inherent in the current method of adding aftertreatment systems to power generation systems. Individual aftertreatment elements are not easily transported via typical shipping methods. In addition, when supporting members are added to the housings of portable power generation systems, the supporting members add width and/or length to the housings. Therefore, these modified housings are often too large to be shipped via conventional means. In fact, special permits are often required to transport such modified housings on highways.
U.S. Pat. No. 4,992,669 issued to Parmley on Feb. 12, 1991 discloses a modular energy system in which a driven unit is connected to a driving unit via a shaft. These modular units are attached to each other via locking assemblies. However, the units that are shown in the '669 patent are each the same size. Stacking such units on top of each other could result in wind loads on the system of sufficient strength to cause damage to the system. In addition, the driven units in the '669 patent do not provide support for internal engine processes but merely use the power created by the driving units.
The power generation aftertreatment system of the present invention solves one or more of the problems set forth above.